A number of different methods and systems are known in the art for creating depth maps. In the present patent application and in the claims, the term “depth map” refers to a representation of a scene as a two-dimensional matrix of pixels, in which each pixel corresponds to a respective location in scene and has a respective pixel depth value, indicative of the distance from a certain reference location to the respective scene location. (In other words, the depth map has the form of an image in which the pixel values indicate topographical information, rather than brightness and/or color of the objects in the scene.) Depth maps may equivalently be referred to as 3D maps, depth images, or 3D images.
Depth maps may be created by various techniques, such as by detection and processing of an image of an object onto which a pattern is projected. Methods of depth mapping of this sort are described, for example, in PCT international Publications WO 2007/043036 A1, WO 2007/105205 and WO 2008/120217, as well as in U.S. Patent Application Publication 2010/0007717, whose disclosures are incorporated herein by reference. Depth maps may alternatively be created by stereoscopic methods or by time-of-flight measurements, as well as by other methods that are known in the art.
Depth maps may be processed in order to segment, identify and localize objects and their components in the scene. Identification of humanoid forms (meaning 3D shapes whose structure resembles that of a human being) in a depth map, and the exact poses of these forms, which may change from frame to frame, may be used as a means for controlling computer applications. For example, PCT International Publication WO 2007/132451, whose disclosure is incorporated herein by reference, describes a computer-implemented method in which a depth map is segmented so as to find a contour of a humanoid body. The contour is processed in order to identify a torso and one or more limbs of the body. An input is generated to control an application program running on a computer by analyzing a disposition of at least one of the identified limbs in the depth map.
U.S. Patent Application Publication 2011/0211754, whose disclosure is incorporated herein by reference, describes a method for tracking body parts by combined color image and depth processing. A part of the body of a subject is identified in at least one of depth image of a scene containing a human subject and receiving a color image of the scene containing the human subject. A quality of both the depth image and the color image is evaluated, and responsively to the quality, one of the images is selected to be dominant in processing of the part of the body in the images. The identified part is localized in the dominant one of the images, while using supporting data from the other one of the images.
Documents incorporated by reference in the present patent application are to be considered an integral part of the application except that to the extent any terms are defined in these incorporated documents in a manner that conflicts with the definitions made explicitly or implicitly in the present specification, only the definitions in the present specification should be considered.